Presettable Up/Down Counter

High-Voltage Silicon-Gate CMOS

The IW4029B consists of a four-stage binary or BCD-decade up/down counter with provisions for look-ahead carry in both counting modes. The inputs consists of a single CLOCK, CARRY IN,(CLOCK ENABLE), BINARY/DECADE, UP/DOWN, PRESET ENABLE, and four individual JAM signals. Q1, Q2, Q3, Q4 and a CARRY OUT signal are provided as outputs.

A high PRESET ENABLE signal allows information on the JAM INPUTS to preset the counter to any state asynchronously with the clock. A low on each JAM line, when the PRESET-ENABLE signal is high, resets the counter to its zero count. The counter is advanced one count at the positive transition of the clock when the CARRY IN and PRESET ENABLE signals are low. Advancement is inhibited when the CARRY IN or PRESET ENABLE signals are high. The CARRY OUT signal is normally high and goes low when the counter reaches its maximum count in the UP mode or the minimum count in the DOWN mode provided the CARRY IN signal is low. The CARRY IN signal in the low state can thus be considered a CLOCK ENABLE. The CARRY IN terminal must be connected to GND when not in use.

Binary counting is accomplished when the BINARY/DECADE input is high; the counter counts in the decade mode when the BINARY/DECADE input is low. The counter counts up when the UP/DOWN input is high, and down when the UP/DOWN input is low.

Parallel clocking provides synchronous control and hence faster response from all counting outputs. Ripple-clocking allows for longer clock input rise and fall times.

• Operating Voltage Range: 3.0 to 18 V

• Maximum input current of 1 μA at 18 V over full package

temperature range; 100 nA at 18 V and 25°C

• Noise margin (over full package temperature range):

1.0 V min @ 5.0 V supply

2.0 V min @ 10.0 V supply

2.5 V min @ 15.0 V supply